In a specific location, such as a train, a library, a museum, or a theater, it is not desirable to make a voice call conversation. For this reason, each user of a mobile communication terminal, such as a portable phone, (hereinafter referred to as “portable phone”) is required to turn off the mobile communication terminal or to set it to a silent mode. When the portable phone is turned off, however, it is not certain whether an incoming call has been received until the portable phone is turned on again, even if there is an incoming call. This may result in a delay of a response to an important call, which is a significant disadvantage for a business user.
When the portable phone is set to the silent mode, a receiver may talk on the phone upon receiving a call, which causes any public nuisance. Therefore, in any case, it is difficult to reliably inhibit a voice call reception, since each user is allowed to configure the setting of his/her portable phone.
Accordingly, conventional portable phone systems are required to have a function of inhibiting a voice call reception in a specific location. For example, in a base station and a portable communication terminal which are disclosed in Patent Literature 1, the base station having a telephone answering function to transmit silent incoming call information is configured for the terminal existing in the base station within an area in which ring tone or communication is inhibited. Further, the portable communication terminal is provided with means for informing and receiving a call by vibration, light, or display of character information onto a light-receiving unit upon receiving a signal from the base station that transmits the silent incoming call information.
Additionally, Patent Literature 2 discloses a mobile communication system in which a particular base station that covers a particular area is not connected to another base station and a higher-level apparatus. The mobile communication system disclosed in this patent literature includes a particular base station (stand-alone) which is not connected to a higher-level apparatus and cannot communicate with the higher-level apparatus. A call transmission and reception service for a mobile station within a communication service area of the particular base station (the position of the mobile station is registered) are stopped because the particular base station is not connected to the higher-level apparatus. When the mobile station within the communication service area of the particular base station (the position of the mobile station is registered) needs to establish communication, the communication service area of the particular base station is released by an operation of the mobile station, which allows the base station to be located within a communication service area of a normal base station. In this case, the mobile station informs the normal base station of an area characteristic code received from the particular base station. The area characteristic code is configured such that refusal of service, such as prohibition of transmission of emails or prohibition of connection to the Internet, is set depending on areas such as a hospital, a train, and a library. The normal base station determines the necessity to limit the service based on the area characteristic code received from the mobile station.